ipv6: invert join/leave anycast rtnl/socket locking order

Commit baf606d9c9b1 ("ipv4,ipv6: grab rtnl before locking the socket")
missed to update two setsockopt options, IPV6_JOIN_ANYCAST and
IPV6_LEAVE_ANYCAST, causing a lock inverstion regarding to the updated ones.

As ipv6_sock_ac_join and ipv6_sock_ac_leave are only called from
do_ipv6_setsockopt, we are good to just move the rtnl lock upper.

Fixes: baf606d9c9b1 ("ipv4,ipv6: grab rtnl before locking the socket")
Reported-by: Ying Huang <ying.huang@intel.com>
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 7 deletions

diff --git a/net/ipv6/anycast.c b/net/ipv6/anycast.c
index baf2742d1ec4..9e6b0ee563f0 100644
--- a/net/ipv6/anycast.c
+++ b/net/ipv6/anycast.c
@@ -60,6 +60,8 @@ int ipv6_sock_ac_join(struct sock *sk, int ifindex, const struct in6_addr *addr)
         int     ishost = !net->ipv6.devconf_all->forwarding;
         int     err = 0;
 
+        ASSERT_RTNL();
+
         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
                 return -EPERM;
         if (ipv6_addr_is_multicast(addr))
@@ -73,7 +75,6 @@ int ipv6_sock_ac_join(struct sock *sk, int ifindex, const struct in6_addr *addr)
         pac->acl_next = NULL;
         pac->acl_addr = *addr;
 
-        rtnl_lock();
         if (ifindex == 0) {
                 struct rt6_info *rt;
 
@@ -130,7 +131,6 @@ int ipv6_sock_ac_join(struct sock *sk, int ifindex, const struct in6_addr *addr)
         }
 
 error:
-        rtnl_unlock();
         if (pac)
                 sock_kfree_s(sk, pac, sizeof(*pac));
         return err;
@@ -146,7 +146,8 @@ int ipv6_sock_ac_drop(struct sock *sk, int ifindex, const struct in6_addr *addr)
         struct ipv6_ac_socklist *pac, *prev_pac;
         struct net *net = sock_net(sk);
 
-        rtnl_lock();
+        ASSERT_RTNL();
+
         prev_pac = NULL;
         for (pac = np->ipv6_ac_list; pac; pac = pac->acl_next) {
                 if ((ifindex == 0 || pac->acl_ifindex == ifindex) &&
@@ -154,10 +155,8 @@ int ipv6_sock_ac_drop(struct sock *sk, int ifindex, const struct in6_addr *addr)
                         break;
                 prev_pac = pac;
         }
-        if (!pac) {
-                rtnl_unlock();
+        if (!pac)
                 return -ENOENT;
-        }
         if (prev_pac)
                 prev_pac->acl_next = pac->acl_next;
         else
@@ -166,7 +165,6 @@ int ipv6_sock_ac_drop(struct sock *sk, int ifindex, const struct in6_addr *addr)
         dev = __dev_get_by_index(net, pac->acl_ifindex);
         if (dev)
                 ipv6_dev_ac_dec(dev, &pac->acl_addr);
-        rtnl_unlock();
 
         sock_kfree_s(sk, pac, sizeof(*pac));
         return 0;